LAB ASCEPTIC.docx

Aseptic Technique 1. What is an aseptic technique and why is it important to use in a Microbiology lab? - Aseptic technique is a set of specific practices and procedures performed under carefully controlled conditions to minimize contamination by pathogens. It is crucial in microbio...

Aseptic Technique 1. What is an aseptic technique and why is it important to use in a Microbiology lab? - Aseptic technique is a set of specific practices and procedures performed under carefully controlled conditions to minimize contamination by pathogens. It is crucial in microbiology labs for isolating and working with pure microbial cultures, preventing the introduction of unwanted organisms that could lead to sample contamination or erroneous results. 2. What is the purpose of sterilizing your loop and culture tubes? - The purpose is to kill any microorganisms that may be present on these tools from previous uses or environmental exposure. Sterilizing loops and tubes ensure that no contaminants are introduced into new cultures or experimental setups, maintaining the purity and integrity of the samples. 3. Describe the process of aseptically working with (inoculating or transferring) bacteria. Inoculating bacteria aseptically involves several steps: a. Sterilize the inoculating loop using a flame until it is red hot, then allow it to cool. b. Remove the cap of the culture tube\*\* being inoculated and flame the mouth of the tube to kill any potential contaminants. c. Obtain a sample of bacteria with the cooled loop. d. Inoculate the sterile medium by streaking the loop across the agar surface or suspending the bacteria in a broth. e. Flame the tube mouth again and replace the cap. f. Sterilize the loop after use to destroy any remaining bacteria. 4. What are the advantages and disadvantages of sterilizing with an autoclave? - Advantages: - Effectiveness: Autoclaves use pressurized steam to achieve high temperatures, effectively killing all types of microorganisms, including spores. - Speed: Sterilization cycles are relatively quick, usually about 15-30 minutes, depending on the load and temperature. - Safety: Reduces the risk of exposure to pathogenic organisms during the sterilization process. - Disadvantages: - Cost: Autoclaves are expensive to purchase and maintain. - Material Limitations: Not all materials can withstand autoclave temperatures, which can limit their use with heat-sensitive items. - Energy Consumption: Autoclaves require significant amounts of energy to operate. Ubiquity of Microbes 1. What is meant by the ubiquity of microbes? Where can microbes be found? - The ubiquity of microbes refers to the fact that microorganisms are found virtually everywhere in the environment. They inhabit soil, water, air, and extreme environments; they also live on and inside other living organisms, making them the most widespread forms of life on Earth. 2. What type of microbes might you expect to grow on your agar plate when sampling from an inanimate object? Why? - Typically, you might expect to find bacteria and fungi that are commonly present in the environment. The types depend on the object\'s exposure to these organisms and could include common environmental bacteria like Bacillus spp. or molds such as Aspergillus spp. These microbes are prevalent due to their ability to survive in diverse conditions with minimal nutrients. 3. What type of microbes might you expect to grow on your agar plate when sampling from your body? Why? - Sampling from the body, especially skin or mucous membranes, typically yields resident flora such as Staphylococcus epidermidis, Propionibacterium acnes, and various yeasts. These organisms are regular inhabitants of human skin and mucosal surfaces, adapted to thrive in these environments. 4. Why is it necessary to use a cotton swab wet with sterilized water when sampling from the lab or body? - A wet swab aids in the collection of microorganisms by ensuring that the cells adhere to the swab. The sterilized water helps in loosening the cells from surfaces without introducing additional contaminants. 5. What type of agar was used to grow these microbes? Is it selective, differential, or general? - This depends on the specific laboratory exercise; however, general-purpose media such as Nutrient Agar or Tryptic Soy Agar are commonly used for such exercises. These media can support the growth of a wide range of bacteria and are neither selective nor differential. If specifics like the inhibition of certain microbes or differentiation among species are needed, selective media (e.g., MacConkey Agar) or differential media (e.g., Blood Agar) would be used. 6. Why are the agar plates placed upside down (agar side up) when placed in the incubator? - Plates are incubated agar side up to prevent condensation on the lid from dripping onto the agar surface, which could spread colonies and disrupt isolated growth.